In Europe, diesel vehicles are popular because the cost of gasoline is so high and diesel motors are usually more fuel-efficient. Relatively cheap gasoline in the United States has left diesel-powered cars without much of a following (Volkswagen has been the only company to stick by diesel-powered cars for the long haul in the U.S.).

However, the push for greater fuel efficiency standards has resulted in more diesel cars being offered within the U.S. Last year, Audi announced that it would be offering four new vehicles with diesel-power within the United States. This week, Audi announced that in addition to those four already announced vehicle, the next generation A4 destined for the U.S. will also have a diesel option. In this case, the A4 will be available with a 2.0-liter, four-cylinder TDI engine.

Current generation Audi A4

Audi of America President Scott Keogh explained the delay in offering a TDI engine on the A4 by stating, "This deep in its life cycle, it didn't make any sense to do all that dramatic re-engineering and re-architecting of the car to basically only have a two-year selling period."

Audi isn't the only automotive manufacturer planning to bring diesel-powered cars to the US. BMW has announced plans for diesels in 2013 and 2014. Mazda has also announced that it will bring its Mazda6 to the U.S. featuring diesel-power.

I'm a diesel fanatic but it continues to disappoint me that I cannot get an all-wheel drive CAR with a diesel engine here in the USA. It doesn't appear the A4 will solve this problem either.

I really liked Audi's A3, which did offer a diesel, but not with AWD. People who live in the snow belt, like me, want AWD and the fuel economy of diesel yet we keep getting denied. You have to buy a $50,000+ SUV to get AWD diesel and that's just not in my budget. I want a hatchback, which is why I really liked the A3.